What volume of carbon (IV) is produced at s.t.p when 2.50g of CaCO3 react with excess acid according to the following equation? CaCO3 + 2HCl → CaCl2 + H2O + CO2 [CaCO3 = 100;molar volume of a gas at s.t.p = 22.4dm3]

2NaNO3 → 2NaNO2 + O2 From the equation above, what is the volume of oxygen produced at s.t.p when 8.5g of NaNO3 is heated until no further gas is evolved? (NaNO3 = 85, molar volume of gas at s.t.p = 22.4dm3 )